Add extern "C" to header files.

Update issue 35
Status: FixedInGit

pb_decode.h

@@ -12,6 +12,10 @@
 #include <stdbool.h>
 #include "pb.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /* Lightweight input stream.
  * You can provide a callback function for reading or use
  * pb_istream_from_buffer.
@@ -102,4 +106,8 @@ bool pb_skip_varint(pb_istream_t *stream);
 bool pb_skip_string(pb_istream_t *stream);
 #endif
 
+#ifdef __cplusplus
+} /* extern "C" */
+#endif
+
 #endif